Triboelectric Nanogenerators for Self-Powered Breath Monitoring

In order for survival, we humans must breathe. The process of breathing involves not only the exchange of oxygen and carbon dioxide but also the exhalation of chemical compounds that can reflect one’s physical health. Additionally, exhaled breath contains many physical properties that can be measured for physiological monitoring. Our ability to control breathing provides a strong foundation for the creation of breath monitoring devices; however, currently existing ones are impractical due to their low portability, need for batteries, difficulty in breath sample collection, and inability for continuous monitoring. One way of combating these issues is through the use of breath-based wearable bioelectronics involving triboelectric nanogenerators (TENGs), a rapidly developing technology that is capable of converting mechanical energy into electricity. Currently, wearable breath monitoring devices based on TENGs have been developed for chemical sensing of compounds that can be indicative of diseases including diabetes, physical sensing of breath patterns and volume, as well as using the breath as a power source for renewable energy. In this review, we provide an overview of the existing TENG-enabled wearable breath monitoring devices as well as a discussion on their future prospects.